Fuel economy regulations are another example, it could be said that they have gone too far, but I have little doubt that if not for regulations, we would still have loads of cars on the market that got lousy gas mileage
Once $4/gal gas hit, sales of SUVs hit the toilet, today with the return of cheap gas even with all the regulation they are again one of the most popular models. Seems now there on track to requirements that may not be technically possible or are our cars become so stupid expensive most can afford them so they stay with their gas hogging clunker. Somewhere their needs to be a sensible balance.
I deal with these credits all the time in building automation. We have pretty substantial credits for putting VFDs on motors where I'm at currently. Sounds like a good idea and it is in a lot of cases. Being the credits are so good, I see a fair deal of these applied to motors that need to run full speed in order to operate the equipment correctly. So they add a VFD, run it @ 100% constantly while taking a 5%eff hit just to collect a wad of cash. Does the program wash out overall, I don't know. I know its my tax money paying for this BS, and there should be enough merit based on the energy savings alone IMO.
When VFDs originally came out, they where expensive as hell in the HVAC field. I don't remember any real credits being handed out then, nothing like they do today. People installed them where they actually had a payback in the energy savings. Somehow they caught on, and now they are common as candy corn in our field.
LED bulbs, I don't see any different. Without any handouts, they are plenty of applications a $25-50 bulb made cents. Bulbs in a auditorium/gym ceilings, billboards, etc where the labor to install them outweighs the cost. Would technology move faster if we shower it in cash, sure. Without any handouts, would LED technology stop dead in its tracks, doubt it.
There are alot of innovations out there that didn't require us showering it with money. If it has merits, people will buy it. More people buy it, costs come down and it snowballs.